Member postings for Neil Lickfold

I trued up a friends new lathe gear, buy just chucking up a piece, and skim the area where the jaws clamp. The bar was skimmed with the tail stock support in place. I used a marker pen to keep the keep the centre and the bar end on about the same radial position. The chuck is tightened on the marked key when the tail stock is in place. I skimmed the face and had to turn the taper register too. Same with the 4 jaw chuck, and then used the 4 jaw to correct the face plate. It was a D1-5 with 6 pins. A quite unusual size. Now his chucks run very well.

My experience with 5c collets is that you get what you pay for. Hardinge make a precision series that are very good. Some cheap ones I got , were rubbish in comparison for concentricity and holding parts true. The emergency collets are great though. You bore them out to the size you want, and will always be concentric in that spindle or adapter. They come in steel, Brass, and even Delrin.

Neil

You still need the tool to be close to the chuck, either internal or external threading. While reverse cutting seems easier because the power feed is away from the chuck, the initial part of getting the tool to the shoulder and then reversing is still there. One advantage of threading in normal rotation towards the chuck, is when you have an older lather or one that has slop in the whole assembly. Starting early takes away that slop and you have a great thread right up until the end. Either option will require a thread relief area. Sometimes it is easier to just turn the machine over manually, with either a hand crank or just turning the chuck with your hands. There is no wrong way to do something. Just that some ways pose more risk or danger than other ways. With internal threading and boring, I often either use a marker pen or paper tape, to visually show the max depth of the part to the cut as a guide. In regards to reducing the chuck from coming loose on the Myford S7 , I have often thought of making a ring collar, with a set screw, and then drilling a matching hole through the back of the chuck body, and use a brass or copper plug to make it lock onto the spindle, like some of the Hardinge chucks have with their screw on fixtures etc. The 4jaw for a Myford S7 would need to be drilled right through for this to be effective, something I am reluctant to do myself. If I find that I need a largish work piece that needs to be cut in reverse and would be putting enough load onto the chuck that a risk of it coming loose could happen, then I would drill a hole through it to make a locking pad. The only reason for making an outer ring to carry the set screw, is to not be distorting the chuck body in some some way with the small diameter flange that is on the chuck backplate.

Most of all, enjoy the model engineering and have fun doing it. It is a great hobby, and many people who are not professional machinist often have great ideas and ways of doing things .

My Assembly arrived today. Sadly it was missing the spring washer or diaphragm washer for the tension on the dial. Anyway, what I really noticed was the pain to get to the 4BA screws holding the nut to the carriage. I found some 4BA set screws 5/8 long with a 1/16 hex in them. Made some nut heads from 1/4 hex brass and glued with 620 loctite. These are much easier for my fingers to access than the long series screw driver. I have a long series 1/16 allen key and is easy to install and a 1/4 spanner to just nip up. This is for using my fine thread assembly that is 1mm/ rev on diameter.

Neil

You can use the clutch to stop the thread cutting very effectively. I don't disengage the half nut when screw cutting. I create a thread runout area, either for the external or internal threads. If the thread pitch is fairly course, ie over 20tpi or over 1.25mm pitch, I just used the back gear to slow it down, to give more time. Then turn off the motor, reverse motor direction, wind away from the cut,(retract the tool) and use the clutch to engage and wind back to the beginning. Now that I have a VFD(variable frequency drive) I use a micro switch to stop the lathe when it gets to the run out area. Seldom do I cut threads without a thread relief area, as it prevents chipping of the threading tool. In this video you can see it stopping in the thread run out area. It generally will stop within 0.1mm every time. By hand , you would run in the lower rpm range and just disengage the clutch.

https://youtu.be/LW1-UfYKGCE

With my new house build, the concrete floor minimum thickness was increased from 50mm for the rest of the house to 100mm for the workshop. I also increased the concrete to 30mpa instead of the std 25mpa, as the higher cement content makes for a slightly nicer finish on the floor as well. The poly styrene under the floor areas that goes down to the base, so makes a concrete rib that is 200mm deep in the workshop and 150mm deep for the rest of the house. The foam is specific for house construction, but I don't know what compressive strength was used. My driveway is cracking and is placed on sand and they did not reinforce it. Not happy about that. The cracks are now happening 2 years latter. It is also only around 75mm thick. Which I think is too thin for an un reinforced structure.

My Approach is different. Use a slightly longer blank than the finished length and bigger than the finished diameter. The very start of the hole for the first 1.5 diameters is the most important. Spot or centre drill the start. Then drill with a slower initial start rpm with the shortest drill you have. In the OP case using a 5.3 or 5.4mm drill. Then when at 1 diameter in, you can then change to the normal drilling speed. Drill right through then ream the hole. I leave the end of the hole sharp, and turn taper to suit the lathe centre for about 1mm long. I then set up a centre in the head stock, and turn the OD true to the hole that has been made between centres. The turned taper sits on the headstock end centre. I rely on the friction drive for the 1mm long to hold the part while I take very fine cuts on the OD. The drilled out end, the sharp end, is the end at the live centre. The stock will be the best average of the generated hole.

Thanks Michael, I just ordered a complete spare cross slide assembly for mine. Just 4 screws and then I can change out from the 2mm pitch metric assembly, to the home made 0.5mm pitch assembly now. The one I made, uses the imperial 100 thou dial, so each division matches 0.01mm diameter on a metric micrometer. Lots more winding of the handle of course, but makes it so much easier if you are making a lot of bits that you need to be as close as possible.

Cheers, and thanks again for the parts in stock heads up.

Having the filament in a box with desiccant is very important. Especially with Nylons to a degree PLA. The worse days is when the humidity is very high in the shop, and you change the filament on that day. Ours is a perspex box with the crystals in the bottom of the box. The crystals can be dried out in the oven over time, or just replace it. We have Bowden tube covering most of the filament as possible. Some printers it is not possible to have a tube covering over the filament all the way to the print head or extruder.

So just needed a lot of persuasion or a really large shock blow to take apart. Was there any damage to the parts at all? I guess a clean and a re lube and good for many more years to come.

The most common cause of the hss getting hot is either the wrong grade of grinding wheel, or it has dulled and needs to be re dressed and sharpened. CBN works very well for hss , but again the wrong grade for roughing out and it all just gets hot. They have cbn dressing sticks as well. When roughing out a new tool I keep it cool by dipping the blank into the water often. When the water starts to bubble or boil, dip again. When the time frame to boil the water near the cutting edge happens inside 10 seconds of grinding, the wheel needs to be de glazed or re dressed again. An open 36 grit wheel is great for roughing out tools, while a 80 to 100 grit is great for the finishing and light touchups. Many just by the finer 40 or 60 grit and try to make that 1 wheel do everything. I only make form tools from hss or tools that the standard shape carbide tools do not cover. I try to grind all the tools with the hss not getting to a light straw colour anywhere. Good hss has red hardness, so can be dull red hot and not have the hardness reduced. For small internal radius on a tool, I use either the desic diamond burs, or dress a mounted point to create that geometry. I find with the dremel stones or the desic diamond points, that a smear of cutting oil helps it cut a lot longer before clogging or going dull. The better the front or cutting surface finish on hss tools , the better the finish on the part, and the longer the tool will last as well. A mirror finished tool will last more than 3 times longer than a just ground tool from a 60 grit stone.

Edited By Neil Lickfold on 26/01/2022 08:27:45

If you copy a top clamp design instead of the offset hole design, you can then have the option of holding ceramic inserts with a substantially reduced risk of cracking them. The top clamp design also hold the inserts a lot better than the offset screw method as well.

The really big advantage of the tangential tools, is that as you regrind, the centre height is easily corrected. Ifanga used to make tangential threading tools too, but not sure if they are available any more.

As to the original question, cut off the end of the tool area that is no longer useful , then create the new shape that is wanted.

In the early days, the HSS tool holders came with the lathes , like Colchester lathes, the 1/4 square and 5/16 square holders, were inclined at about 5deg or 8 deg, and also had a side angle of about 2 or 3 deg. So the tools only required the font to be ground, and the side relief to be ground. The top already had the relief from the holder.

Neil

If you get it Hard anodised, it will work well. Another upgrade is the use of thin Turcite in the gib as well. There was someone offering Acetyl gib upgrades for both the Sherline and Taig lathes a few years ago. 6082 is a nice stable easy to cut alloy that also anodises very well. Some are making their own top slide that incorporates the tool holder in the block to take the standard shank insert tooling as well.

Be nice to see what you make if you can share images of the build.

Can you use another material instead of the ABS? ABS is terrible stuff to try and glue to, especially when a peel strength is required.

With my mill drill, I put the MT4 arbour in the mill and kept rotating it in the spindle, to the place of the least runout with an indicator. Marked a 0 on the arbour to match the 0 that was already on the spindle dog. Then put a 6mm pin into the chuck, and kept moving that around until the pin had the lowest run reading and pushed the chuck by had at that point. checked again. Then used some different sized tools to see how they looked, like 4mm, 8mm and 10mm. Sometimes you get lucky and find the best place quite easy with some chucks, others not so lucky. Not sure who actually makes the Niraw brand sold out here with a picture of a whale on it's side. But very reasonable priced cucks with very good accuracy. I did get one that has the body integral with the MT4 arbour(Not the Niraw), and it has about 0.1 to 0.12 mm runout when fiddled with. I know that my spindle is not totally true, but is not 0.1mm out that's for sure. It does seem unusual to see such a gap between the chuck and the mandrel though. With the 4mm and 6mm carbide reamers, my good chuck runs better than 0.02mm tir. So it is only used for the work that is going to use the carbide reamers. Otherwise for clearance, holes the integral one is used. In doing the exercise, I did find that carbide blanks and pins that I thought were straight, really were quite bent, and throwing off the initial readings. The integral chuck still puts holes in quite accurately despite the run out of things. So the drills must be flexing a bit somewhere and following the spot drilled or centre drilled holes quite well.

Be interesting to see how your one turns out after the trial and error.

ATF(Automatic transmission Fluid) oil work very well for lathe gear boxes. The advantage of the AFT oils , is that they have buffers for acid and for alkalines as well. Can cope with lots of differing materials as well. It's also sold in 1l packs as well.

A photo of the worst rusted slip will help as to what the best way is to recover the gauge. White vinegar and salt can help to get rid of light rust. It can be micro lapped on a lapped flat piece of artificial granite square sample piece, and use 0.5 micron diamond. It will require a holder to push down onto the block, so you are distorting or lapping it on a strange shape. Seldom do damaged slips wring correctly again. They will still be useful for lots of things however. I would stay away from things like wet dry paper or even Scotchbrite.

What a great read. You can make your own other probes for the Blake indicator. I would suspect that the 8 spares may still work. I made some for specific jobs, and the one I use the most is about 1/2 the length of the standard supplied probe. It works really well when height is restricted, and when only doing small diameter bores.

I turn it round by hand until it is less than 1 turn out, and then start the mill. Mine is the ht for a long time it was 1metric 0.01mm per division and got it in 1987.

A friend is looking at something similar that makes 380v from 220-240v input, but can go up to 60hz, not just the 50hz as the input voltage. So it replicates connecting to a 3phase power supply 380v 60hz. The one he is looking at is not intended to be variable on the 380v output. He has a Hardinge small milling machine that has a constant torque 2 speed motor.

Is there any more information on the units in your link? My simple search came up with not much. Be nice to look at a user manual for one.

Thanks Neil